<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./js/vue.js"></script>
    
</head>
<body>
    <div id="app">
        <input type="text" placeholder="请输入小写字母" v-model="msg"/>
        </br>
        <button v-on:click="big">点击转大写</button>  
    </div>
    <script>
        let app = new Vue({
            el:"#app",
            data:{
                msg:"",
            },
            methods:{
                big: function() {
                    this.msg = this.msg.toUpperCase();
                },
            },
        });

            
    </script>
</body>
</html>